This section is intended to provide a background or context to the invention disclosed below. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise explicitly indicated herein, what is described in this section is not prior art to the description in this application and is not admitted to be prior art by inclusion in this section. Abbreviations that may be found in the specification and/or the drawing figures are defined below, after the main part of the detailed description section.
Geographic positioning of mobile terminals is used for various purposes, such as emergency calls for first responders for example. Often times, a mobile terminal's geographic positioning can be determined through a global positioning system (GPS). However, there are times when GPS is unable to determine the location of a mobile terminal accurately such as when there is a lack of clear line of sight. Further, not every mobile terminal has a GPS capability. In these cases, a wireless network may provide assistance so that the mobile terminal may accurately determine its geographic position. Observed time difference of arrival (OTDOA) positioning is one solution which uses signal from neighbor cells to calculate an observed time different of arrival relative to the service cell (or another designated reference cell) of the mobile terminal. LTE LPP specification 3GPP TS 36.355 provides details on OTDOA positioning.